#include<stdio.h>
float fact(int n);
void main()
{
	float sum = 0.0;
	int k = 0;
	for (k = 1; k <= 19; k = k + 2)
	{
		sum = sum + fact(k);
	}
	printf("sum=%.1f\n", sum);

}
float fact(int n)
{
	int i=0;
	float t = 1.0;
	for (i = 2; i <= n; i++)
		t = t * i;
	return t;
}